#include <stdio.h>
#include <stdlib.h>
#define MAXTITL 40
#define MAXAUTL 40
#define MAXBKS 10
struct book
{
    char title[MAXTITL];
    char author[MAXAUTL];
    float value;
};
int main(void)
{
    struct book library[MAXBKS];
    int count = 0;
    int index, filecount;
    FILE * pbooks;
    int size = sizeof(struct book);
    if((pbooks = fopen("3.txt", "a+b")) == NULL)
    {
        fputs("Can't open 3.txt file\n", stderr);
        exit(1);
    }
    rewind(pbooks);
    while(count < MAXBKS && fread(&library[count], size, 1, pbooks) == 1)
    {
        if(count == 0)
            puts("Current contents of 3.txt.");
        printf("%s by %s: $.2f\n", library[count].title, library[count].author, library[count].value);
        count++;
    }
    filecount = count;
    if(count == MAXBKS)
    {
        fputs("The 3.txt file is full.\n", stderr);
        exit(2);
    }

    puts("Please add new book titles.");
    puts("Press [Enter] at the start of a line to stop.");
    while(count < MAXBKS && gets(library[count].title) != NULL && library[count].title[0] != '\0')
    {
        puts("Now enter the author.");
        gets(library[count].author);
        puts("Now enter the value.");
        scanf("%f", &library[count++].value);
        while(getchar() != '\n')
            continue;
        if(count < MAXBKS)
            puts("Enter the next title.");
    }
    if(count > 0)
    {
        puts("Here is the list of your books:");
        for(index = 0; index < count; index++)
            printf("%s by %s: $%.2f\n", library[index].title, library[index].author, library[index].value);
        fwrite(&library[filecount], size, count - filecount, pbooks);
    }
    else
        puts("No books? Too bad.");
    puts("Bye.\n");
    fclose(pbooks);
    return 0;
}
